History

kconfig: simplification of scripts/extract-ikconfig

I've rewritten the extract-ikconfig script to extract the kernel configuration from a kernel compiled with CONFIG_IKCONFIG. The main motivation for the rewrite was to remove the dependency on the external C program binoffset.c, which is compiled on the initial run. The binoffset executable is invoked with a relative path, which means that the old script can only be run from the top of the kernel tree, and only when you have write permission in the scripts directory. The new script uses tr/grep/tail/zcat only, and can be invoked from anywhere. The binoffset.c program has been removed. This script requires GNU grep 2.5 (released 2002-03-13) or higher, because the -o option was introduced in that version.

Dick Streefland committed 17 years ago

Commit 7b76bfc1 parent 0eca52a4 files · +44 −248Browse files

Unified · Split

4 files
  1. Documentation/dontdiff +0 −1
  2. scripts/.gitignore +0 −1
  3. scripts/binoffset.c +0 −163
  4. scripts/extract-ikconfig +44 −83
Documentation/dontdiff+0−1
@@ -68,7 +68,6 @@ autoconf.h* · 67 unmodified lines
6868 bbootsect
6969 bin2c
7070 binkernel.spec
71−binoffset
7271 bootsect
7372 bounds.h
7473 bsetup
scripts/.gitignore+0−1
@@ -6,5 +6,4 @@ kallsyms · 5 unmodified lines
66 pnmtologo
77 bin2c
88 unifdef
9−binoffset
109 ihex2fw
scripts/binoffset.c+0−163
@@ -1,163 +0,0 @@
1−/***************************************************************************
2− * binoffset.c
3− * (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
4−
5−# This program is free software; you can redistribute it and/or modify
6−# it under the terms of the GNU General Public License as published by
7−# the Free Software Foundation; either version 2 of the License, or
8−# (at your option) any later version.
9−#
10−# This program is distributed in the hope that it will be useful,
11−# but WITHOUT ANY WARRANTY; without even the implied warranty of
12−# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13−# GNU General Public License for more details.
14−#
15−# You should have received a copy of the GNU General Public License
16−# along with this program; if not, write to the Free Software
17−# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18−
19−# binoffset.c:
20−# - searches a (binary) file for a specified (binary) pattern
21−# - returns the offset of the located pattern or ~0 if not found
22−# - exits with exit status 0 normally or non-0 if pattern is not found
23−# or any other error occurs.
24−
25−****************************************************************/
26−
27−#include <stdio.h>
28−#include <stdlib.h>
29−#include <string.h>
30−#include <errno.h>
31−#include <unistd.h>
32−#include <fcntl.h>
33−#include <sys/types.h>
34−#include <sys/stat.h>
35−#include <sys/mman.h>
36−
37−#define VERSION "0.1"
38−#define BUF_SIZE (16 * 1024)
39−#define PAT_SIZE 100
40−
41−char *progname;
42−char *inputname;
43−int inputfd;
44−unsigned int bix; /* buf index */
45−unsigned char patterns [PAT_SIZE] = {0}; /* byte-sized pattern array */
46−int pat_len; /* actual number of pattern bytes */
47−unsigned char *madr; /* mmap address */
48−size_t filesize;
49−int num_matches = 0;
50−off_t firstloc = 0;
51−
52−void usage (void)
53−{
54− fprintf (stderr, "%s ver. %s\n", progname, VERSION);
55− fprintf (stderr, "usage: %s filename pattern_bytes\n",
56− progname);
57− fprintf (stderr, " [prints location of pattern_bytes in file]\n");
58− exit (1);
59−}
60−
61−void get_pattern (int pat_count, char *pats [])
62−{
63− int ix, err, tmp;
64−
65−#ifdef DEBUG
66− fprintf (stderr,"get_pattern: count = %d\n", pat_count);
67− for (ix = 0; ix < pat_count; ix++)
68− fprintf (stderr, " pat # %d: [%s]\n", ix, pats[ix]);
69−#endif
70−
71− for (ix = 0; ix < pat_count; ix++) {
72− tmp = 0;
73− err = sscanf (pats[ix], "%5i", &tmp);
74− if (err != 1 || tmp > 0xff) {
75− fprintf (stderr, "pattern or value error in pattern # %d [%s]\n",
76− ix, pats[ix]);
77− usage ();
78− }
79− patterns [ix] = tmp;
80− }
81− pat_len = pat_count;
82−}
83−
84−void search_pattern (void)
85−{
86− for (bix = 0; bix < filesize; bix++) {
87− if (madr[bix] == patterns[0]) {
88− if (memcmp (&madr[bix], patterns, pat_len) == 0) {
89− if (num_matches == 0)
90− firstloc = bix;
91− num_matches++;
92− }
93− }
94− }
95−}
96−
97−#ifdef NOTDEF
98−size_t get_filesize (int fd)
99−{
100− off_t end_off = lseek (fd, 0, SEEK_END);
101− lseek (fd, 0, SEEK_SET);
102− return (size_t) end_off;
103−}
104−#endif
105−
106−size_t get_filesize (int fd)
107−{
108− int err;
109− struct stat stat;
110−
111− err = fstat (fd, &stat);
112− fprintf (stderr, "filesize: %ld\n", err < 0 ? (long)err : stat.st_size);
113− if (err < 0)
114− return err;
115− return (size_t) stat.st_size;
116−}
117−
118−int main (int argc, char *argv [])
119−{
120− progname = argv[0];
121−
122− if (argc < 3)
123− usage ();
124−
125− get_pattern (argc - 2, argv + 2);
126−
127− inputname = argv[1];
128−
129− inputfd = open (inputname, O_RDONLY);
130− if (inputfd == -1) {
131− fprintf (stderr, "%s: cannot open '%s'\n",
132− progname, inputname);
133− exit (3);
134− }
135−
136− filesize = get_filesize (inputfd);
137−
138− madr = mmap (0, filesize, PROT_READ, MAP_PRIVATE, inputfd, 0);
139− if (madr == MAP_FAILED) {
140− fprintf (stderr, "mmap error = %d\n", errno);
141− close (inputfd);
142− exit (4);
143− }
144−
145− search_pattern ();
146−
147− if (munmap (madr, filesize))
148− fprintf (stderr, "munmap error = %d\n", errno);
149−
150− if (close (inputfd))
151− fprintf (stderr, "%s: error %d closing '%s'\n",
152− progname, errno, inputname);
153−
154− fprintf (stderr, "number of pattern matches = %d\n", num_matches);
155− if (num_matches == 0)
156− firstloc = ~0;
157− printf ("%ld\n", firstloc);
158− fprintf (stderr, "%ld\n", firstloc);
159−
160− exit (num_matches ? 0 : 2);
161−}
162−
163−/* end binoffset.c */
scripts/extract-ikconfig+44−83
@@ -1,92 +1,53 @@
11 #!/bin/sh
2−# extracts .config info from a [b]zImage file
3−# uses: binoffset (new), dd, zcat, strings, grep
4−# $arg1 is [b]zImage filename
5−
6−binoffset="./scripts/binoffset"
7−test -e $binoffset || cc -o $binoffset ./scripts/binoffset.c || exit 1
8−
9−IKCFG_ST="0x49 0x4b 0x43 0x46 0x47 0x5f 0x53 0x54"
10−IKCFG_ED="0x49 0x4b 0x43 0x46 0x47 0x5f 0x45 0x44"
11−dump_config() {
12− file="$1"
13−
14− start=`$binoffset $file $IKCFG_ST 2>/dev/null`
15− [ "$?" != "0" ] && start="-1"
16− if [ "$start" -eq "-1" ]; then
17− return
18− fi
19− end=`$binoffset $file $IKCFG_ED 2>/dev/null`
20− [ "$?" != "0" ] && end="-1"
21− if [ "$end" -eq "-1" ]; then
22− return
23− fi
24−
25− start=`expr $start + 8`
26− size=`expr $end - $start`
27−
28− dd if="$file" ibs=1 skip="$start" count="$size" 2>/dev/null | zcat
29−
30− clean_up
31− exit 0
32−}
33−
34−
35−usage()
36−{
37− echo " usage: extract-ikconfig [b]zImage_filename"
38−}
39−
40−clean_up()
2+# ----------------------------------------------------------------------
3+# extract-ikconfig - Extract the .config file from a kernel image
4+#
5+# This will only work when the kernel was compiled with CONFIG_IKCONFIG.
6+#
7+# The obscure use of the "tr" filter is to work around older versions of
8+# "grep" that report the byte offset of the line instead of the pattern.
9+#
10+# (c) 2009, Dick Streefland <dick@streefland.net>
11+# Licensed under the terms of the GNU General Public License.
12+# ----------------------------------------------------------------------
13+
14+gz1='\037\213\010'
15+gz2='01'
16+cf1='IKCFG_ST\037\213\010'
17+cf2='0123456789'
18+
19+dump_config()
4120 {
42− if [ "$TMPFILE" != "" ]; then
43− rm -f $TMPFILE
21+ if pos=`tr "$cf1\n$cf2" "\n$cf2=" < "$1" | grep -abo "^$cf2"`
22+ then
23+ pos=${pos%%:*}
24+ tail -c+$(($pos+8)) "$1" | zcat -q
25+ exit 0
4426 fi
4527 }
4628
47−if [ $# -lt 1 ]
29+# Check invocation:
30+me=${0##*/}
31+img=$1
32+if [ $# -ne 1 -o ! -s "$img" ]
4833 then
49− usage
50− exit 1
34+ echo "Usage: $me <kernel-image>" >&2
35+ exit 2
5136 fi
5237
53−TMPFILE=`mktemp -t ikconfig-XXXXXX` || exit 1
54−image="$1"
55−
56−# vmlinux: Attempt to dump the configuration from the file directly
57−dump_config "$image"
58−
59−GZHDR1="0x1f 0x8b 0x08 0x00"
60−GZHDR2="0x1f 0x8b 0x08 0x08"
61−
62−ELFHDR="0x7f 0x45 0x4c 0x46"
63−
64−# vmlinux.gz: Check for a compressed images
65−off=`$binoffset "$image" $GZHDR1 2>/dev/null`
66−[ "$?" != "0" ] && off="-1"
67−if [ "$off" -eq "-1" ]; then
68− off=`$binoffset "$image" $GZHDR2 2>/dev/null`
69− [ "$?" != "0" ] && off="-1"
70−fi
71−if [ "$off" -eq "0" ]; then
72− zcat <"$image" >"$TMPFILE"
73− dump_config "$TMPFILE"
74−elif [ "$off" -ne "-1" ]; then
75− (dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \
76− zcat >"$TMPFILE"
77− dump_config "$TMPFILE"
78−
79−# check if this is simply an ELF file
80−else
81− off=`$binoffset "$image" $ELFHDR 2>/dev/null`
82− [ "$?" != "0" ] && off="-1"
83− if [ "$off" -eq "0" ]; then
84− dump_config "$image"
85− fi
86−fi
87−
88−echo "ERROR: Unable to extract kernel configuration information."
89−echo " This kernel image may not have the config info."
90−
91−clean_up
38+# Initial attempt for uncompressed images or objects:
39+dump_config "$img"
40+
41+# That didn't work, so decompress and try again:
42+tmp=/tmp/ikconfig$$
43+trap "rm -f $tmp" 0
44+for pos in `tr "$gz1\n$gz2" "\n$gz2=" < "$img" | grep -abo "^$gz2"`
45+do
46+ pos=${pos%%:*}
47+ tail -c+$pos "$img" | zcat 2> /dev/null > $tmp
48+ dump_config $tmp
49+done
50+
51+# Bail out:
52+echo "$me: Cannot find kernel config." >&2
9253 exit 1